Internal combustion engine



INTERNAL COMBUSTION ENGINE Filed March 22. 1930 4 Sheets-Sheet l fig.

% I gwogntoz Julius SckuZerZ Straw June 12, 1934.

J. SCHUBERT 1,962,530

INTERNAL COMBUSTION ENGINE Filed March 22, 1930' 4 Sheets-Sheet 2 J. SCHUBERT INTERNAL COMBUSTION ENGINE June 12, 1934.

Filed March 22, 1930 4 Sheets-Sheet 3 June 12, 1934. J. SCHUBERT INTERNAL COMBUSTION ENGINE 1930 4 Sheets-Sheet 4 Filed March 22 A E////////f///////////////////////A/// 4 W We 3 A w 5. w M J m W g wn T w w a fl 0 flw w 4 6A xi 44 I wherein:

as... at... 12, 1934 1,9 2,530

PATENT OFFICE UNITE TA,

0 INTERNAL coMBUs'rIoN Enema v.iuiius Schubert, Woodside, NIY.

Application March 22, 1930, Serial No. 438,209 13 (01. 123-11) This invention relates to internalcombustion engines and, among other objects, aims to provide an improved, two-cycle, radial engine capable of use in the aircraft, industrial and automotive fields. One of the main objects is to provide a highly efiicient, durable, lightweight engine housing a minimum number of working parts subject to wear.

- Other aims and advantages of the invention will appear in the specification when considered in connection with the accompanying drawings,

ducing weight and increasing power, as well as counterbalancing the working parts, it has been found that the above described type of engine is also inefficient, if not wholly impracticable, largely because of improperfuel distribution and timing, as well as many inherent mechanical defects in the proposed designs. Moreover, the idea 'of using so-called stepped pistons has been considered wholly impracticable by many of the best engineers because they are subjected to unequal expansion and contraction and will crack if they are not properly designed.

This invention provides a highly eflicient, compact, well balanced, lightweight, two-cycle, radial engine that overcomes allof the foregoing difficultiesand especially designed to displace the usual heavy, complex and expensive four-cycle engines now in general use.

' Fig. 1 is a front elevation of the preferred-form of radial engine wherein the cylinders are arranged in two rows or sets,-two of the cylinders being shown in sections taken on different planes;

' Fig. 2 is a side elevation, parts being shown in section;

Fig. 3 is a fragmentary side elevation of the crank shaft and showing one of the cylinders in nating all valves, cam shafts, rocker arms,'springs section; and other valve operating mechan sms, so that Fig. 4 is a sectional view taken on the line44 the pistons, connecting rods and the crank shaft of Fig. 3; are the only moving parts.

Referring particularly to the drawings, the

selected embodiment of the engine is there shown as being applicable to aircraft, being air cooled. However, it is to be understood that it can easily be applied to automobiles, motor boats and the like or'utilized as a stationary or portable power plant when lightweight and high efficiency and economical operation are desired. In some instances, it is contemplated the engine shall be water cooled, especially for stationary or automotive use. In Figs. 1 and 2, the engine is shown as having a substantially cylindrical crank case 10 which is conveniently made in two complemental, longitudinal sections presenting transverse walls 12 and 13 near the ends, providing main crank-shaft bearings 14 and 15. Each end wall preferably has a series of radial strengthening webs 16 (Fig. 2) so that it may be made light. These webs also preferably extend longitudinally of walls between the cylinders. Both sections are preferably cast of aluminum from diflerent patterns and have a series of alined longitudinal ribs 1'7 through which holes are drilled to receive tiebolts 18 to assemble the sections.

Within the crankcase, there is shown con1'- posite crank shaft 19 having crank pins 20 arranged-180 apart (see Figs. 1 and 3), the two pins Fig. 5 is a fragmentary sectional view taken on the line 55 of Fig. 3; r

Fig. 6 is a perspective view showing a roller bearing cage for one of the connecting rods;

Fig. '7 is a fragmentary sectional view of the inner end of a connecting rod;

Fig. 8 is a fragmentary developed horizontal section showing the interior of the lower part of the crank case and the inner ends 'of. the two lower cylinders; and 1' Fig. 9 is a schematic view showing the relative positions of the pistons and their connections to the crank shaft.

Although many attempts have heretofore been made to: produce a practical two-cycle" engine suitable for aircraft or other power plants, they have failed for many reasons. Chief among them is the fact that no one-,as far as I am aware, has succeeded in getting the proper lubrication, cooling, fuel distribution, volumetric and thermal efficiency, power, speed and low weight which are some of the'most essential factors in the design of such engines. Ordinary two-cycle engines having crank case compression are too memcient and heavy for most purposes.

In an effort to increase the volumetric efliciency, some attempts have been made to provide. :fuel orgas pumping pistons associated with the power pistons of radial engines in which all of being forged on a central cheek plate 21 and prethe pistons are connected to a' single crank. senting reduced or shouldered ends 22 suitably While the radial arrangement ofthe power cylii1---secured in openings provided in counterweighted ders arounda crank case-is most desirable for reend cheek plates 23. The crank shaft is jour- The number of working parts is reduced to a minimum by 'eliminaled in the main bearings 14 and 15 preferably having anti-friction bearings 24 as shown in Fig. 2. A propeller or driving shaft 25 projects through the front wall and a driving shaft 26 for a generator and timer projects rearwardly from the rear wall.

In this example, there are two circumferential, overlapping rows or sets of radial cylinders 27, 28, 29, 30, 31 and 32 (Figs. 1 and 9), three cylinders being arranged in each set 120 apart and being staggered with respect to the cylinders in the other set, while the adjacent cylinders are 60 apart. An odd number of cylinders in each row or set is preferred so that the cylinders can be arranged in opposed pairs and simultaneous explosions may reduced or stepped extensions 33 of cylindrical castings 34 which are secured to bosses 35 around the cylinder openings in the crank case. The power cylinders and their heads 36 are conveniently held assembled by tie-bolts 3'7 screwed into bosses 38 on the reduced extensions 33, said bolts also passing through alined openings in bosses 39 on the cylinder heads and being screw threaded at their outer ends to receive nuts 40.

The inner enlarged portions or cylindrical castings 34 are utilized as housings for fuel pumping cylinders, each comprising a relatively thin, cylindrical sleeve 41 telescoped and shrunk into the cylinder castings and presenting intermediate annular shoulders or beads 42 seated in annular grooves or channels 43 in the bases of the castings. The inner ends of the sleeves project into the crank case and the inner edges of the shoulders 42 are seated against the flat bosses around the cylinder openings flush with the bases of the cylindrical castings 34.

Within each of the power cylinders is a power piston 44 which has a stepped and enlarged fuel piston 45 cast integral with its inner end, the arrangement being such that the annular space between the power piston and the fuel pump cylinder is utilized as the fuel compression chamber from which fuel mixture, taken from the crank case, is delivered to an adjoining or adjacent power cylinder in the other row of cylinders. These pistons are hollow and are preferably cast in one piece having their opposed pairs of strengthening webs extending throughout'their length (Fig. 3). They are connected to the respective crank pins 20 by means of specialconnecting rods 46 which are pie-assembled on the crank shaft in the process of assembling the crank shaft parts as previously described. Alternate pistons as shown in Fig. 9 or the pistons in each row or set of cylinders are all connected to the same crank pin.

' Each connecting rod is here shown as being I-shaped in cross section and having a roller bearing on its crank pin. In this example, the openings in the inner ends of the connecting rods are machined, so that they are channel-shaped and present radial inwardlyprojecting' flanges 46' at the opposite sides. A cylindrical ring 4'! of the same width as the'thllaczekrsiliesspgi"i $22000;- necting rods is adapted to p e openingsanslspantheinneredgesofthe 46'. This ring or cage presents a series of rectangular slots 48 into which are inserted hardened cylindrical rollers, a series of axially alined pairs of rollers 49 being preferred in this instance. The arrangement is such that the rollers are adapted to contact with the bottom of the channel and abut the inner faces of the flanges 47 as clearly shown in Fig. 3. One of the cages is first inserted in the connecting rod opening and the rollers are adapted to be set in place in the rectangular openings while the cage is held in vertical position. All of the rollers may be held in place by a suitable thin collar (not shown) while the connecting rod is being slipped over its crank pin.- Thus, when the connecting rods are assembled, the roller bearing members are retained in their bearing grooves and prevent the cylindrical cages from being displaced. The opposite sides of the connecting rods are case hardened so as to reduce wear where they contact with each other.

Referring now to the composite or stepped pistons and their cylinders, ,(Figs. 1 and 3), the inner ends of the fuel cylinders or sleeves 41 which project into the crank case are provided with a series of fuel intake ports 50 adapted to be uncovered by the fuel pistons 45 when they reach the inner ends of their strokes. As these pistons move inwardly, a partial vacuum is created within the fuel cylinders and, as soon as the ports are uncovered, the fuel is sucked into the cylinders, thereby maintaining a partial vacuum when the engine is running. As the pistons move outwardly, the fuel mixture is compressed so that it may be discharged under pressure into one of the power cylinders.

In this example, the inner ends of the working or power cylinders project slightly into the fuel compression space as clearly shown in Figs. 1 and 3, this being necessary to prevent the inner piston ring from slipping out 01' its groove when the piston is at the inner end of its stroke. The fuel pistons are each shown as having an annular groove 51 around the extension of the power piston to accommodate the inwardly projecting ends of the power cylinders. This arrangement enables the cylinder assembly to be made much shorter. Moreover, the grooves permit relative expansion and contraction of the power and fuel pistons. The fuel piston is kept cooler than the power piston and, hence, there is relative expansion when the engine is started. The grooves provide in efiect annular corrugations that take care of this expansion. Further, any oil that accumulates in the groove or around the inner end of the power cylinder will be forced into the pow- .er cylinder when the fuel piston reaches the outer end of its stroke, thus providing an oil seal around the power piston.

At the outer end of each fuel cylinder in the enlarged cylinder casting 34 is a cored port opening 52 with which a series of ports 53 in the sleeve registers and this port is connected by a fuel conduit 55 to a fuel intake port 56 through the reduced cylindrical extension 33 and the telescoped reduced wall portion of the next power cylinder. The ends of the fuel mixture conduits are shown as being flanged and bolted to flat faces machined on the cylindrical extensions 33. In Fig. 1, it will be noted that the crank shaft rotates clockwise and that each fuel pump is connected to supply fuel mixture into the adjacent power cylinder behind it. That is to say, the fuel pump at the inner end of cylinder 29 supplies fuel to power cylinder 28. etc., the conduits being connected zig-zag fashion to supply fuel to the staggered power cylinders one after another in each row. This arrangement is important because of the relative positions of the pistons. A fuel piston in this instance is nearing the outer end of its compression stroke when the piston in the power cylinder towhich it pumps fuel is at the extreme inner or intake end of its stroke (see the piston is utilized to scavenge exhaust gases through excharge with the exhaust gases.

Fuel mixture to which a small quantity of lu-- haust ports 57 on the opposite sidesof the cylinders from the intake portsto'which suitable flanged and rearwardly bent exhaust conduits 58 are connected. The ends of the pistons are shaped as usual to direct the incoming fuel out-' wardly into the cylinders so that it will not dis bricating oil has been added is admitted or supplied to the crank case by a carburetor 59 of any suitable or conventional. design which is connected to a flanged conduit 60 projecting downwardly from the rear crank case section '(Fig. 2). Some of the lubricating oil condenses in the crank case and is deposited on the bearings to afford p'roperlubrication. Very little oil, however, is required for the special anticipation crank shaft and crank pin bearings.

To prevent any accumulated oil in the bottom of the crank case from entering the intake ports 5!) of the pump cylinders adjacent to the carburetor conduit 60, the ports 50 may be arranged in the sides of :the sleeves facing the front end wall or web of the crankcase and sheet metal plates 61' are shown as being secured to the radial and longitudinal ribs 16 and bent upwardly at their front ends (Fig. 3) so as to provide channels through which the fuelmixture enters the two lower cylinders. These plates also prvent any oil from being thrown centrifugally by the cranks and end checks into the fuel mixture. While such channels or conduits may be provided for all of the fuel cylinders, itis not necessary. Obviously, oil screens -or filtering devices-and recovering means may be employed to" prevent any excess of oil from entering the cylinders and fouling-the spark plugs.

Since the engine operates on the two-cycle principle, an explosion occurs in each power cylinder for each revolution of the crank shaft, the explosions in this instance being simultaneous in opposedrcylinders or pairs; hence, the fuel pumps take in as many charges of fuel mixture per revolution 'as there are cylinders. This maintains a constant partial vacuum in the crank case .and the cool fuel mixture entering it pre-' vents the bearings, pistons and cylinders, from overheating. The cooling effect is increased by causing the fuel to flow crosswise in the fuel cylinders, being discharged on one side and admitted on the other side, thereby cooling the cylinders and pistons around practically their entire circumference.

As shown in Fig. 2, a cast metal housing or casing 62 is bolted to the rear wall 13 of the crank caseand an ordinary electric generator and engines.

timer -(not shown) of conventional design are carried in this housing. A frusto-conical hous'-' ing 63 is shown as being secured to the front end of the crank case to provide a front anti-friction bearing 64 for the drive shaft 25 to which a propeller 65 is secured.

In Fig. 2, the tie-bolts 17 for the crank case sections are shown as having annular shoulders 66 set in counter-bores in the rear end wall of the rear section and these bolts, of which there are six between the cylinder openings, have screw threaded ends 6'7 by which a supporting plate 68 is secured to the crank case. This plate has an opening of larger diameter than the housing 62,

so that it can be slipped over the housing and a. series of holes are drilled in it to receive the threaded ends 67 of the tie-bolts; nut 69 secur ing it in-place. Suitable clevis bolts 70 are secured to the plate and brackets'll are connected to these bolts so as to support the engine properly spaced from a fuselage (not shown). -It is contemplated that the engine may be supported either horizontally or vertically, depending upon the particular requirements.

From the foregoing description, it will be seen that all of the engine parts are very simple and there are no delicate exposed working parts which require any adjustment. with air cooling fins or a water jacket, may be alike and cast in two parts which are easily assembled and removed for repairs or replacement.

.Also, all of the stepped pistons and connecting made as little as one pound or even less per horse powerin large sizes. This has been considered almost impossible in connection with other types of engines, particularly the old types of two-cycle In short, this invention makes a twocycle engine available for a wide variety of uses, and is a revolutionary improvement in the aircraft and automotive fields.

Obviously, the present invention is not restricted to the particular embodiment thereof herein shown and described. Moreover, it is not indispensable that all the features of the invention be used conjointly, since they may be employed advantageously in various combinations and sub-combinations.

What I claim is: v

1. A two-cycle internal combustion engine of the class described comprising, in combination, a stationary crank case; a plurality of radial cylinders arranged in two circumferential rows, the cylinders in one row beingstaggered with respect to the cylinders in the other row and being ar- The cylinders, either ranged in diametrically opposed and offset pairs;

, the respective gered with respect to the cylinders in the other row and being arranged in diametrically opposed and offset pairs so that simultaneous explosions in the pairs counteract each other; the pistons in the two rows being connected to a pair of opposed cranks; fuel (charging cylinders coaxial with the working cylinders and extending into the crank case; fuel pumping pistons integral with power pistons in said charging cylinders; and conduits connecting the charging cylinders of each row to the next adiacent working cylinders in the other row.

3. A two-cycle internal combustion engine of the class described comprising, in combination, a crank case; a plurality of radial cylinders arranged in two circumferential rows, the cylinders in one row being staggered with respect to the cylinders in the other row and being arranged in diametrically opposed and offset pairs, the pistons in the two rows being connected to a pair of opposed cranks so that explosions will occur simultaneously in the opposed cylinders; cylindrical ported sleeve members providing fuel charging cylinders coaxial with the working cylinders and projecting into the crank case; fuel vDumping pistons within said sleeves connected to the power pistons; and conduits connecting each of the charging cylinders to the next adjacent power cylinder in the other row.

. 4. A two-cycle internal combustion engine comprising, in combination, a crank case; a crank shaft in the crank case having a pair of cranks arranged 180 degrees apart; sets of radial D wer cylinders for each crank connected to the crank case, the cylinders in each set being offset longitudinally with respect to the crank shaft and the cylinders of one set being staggered with respect to the cylinders in the other set; power pistons in said cylinders: connecting rods for one set of pistons connected alongside of each other to one of the cranks; connecting rods for the other set of pistons similarly connected to the other crank; a fuel pump associated with each piston and connected to deliver fuel under pressure to the' adjacent power cylinder in the other set; and means to supply fuel mixture through the crank case to the fuel pumps.

5. A two-cycle internal combustion engine comprising, in combination, a crank case; a crank shaft in the crank case having a pair of cranks arranged 180 degrees apart; two. circumferential and overlapping sets of radial power cylinders for each crank connected to the crank case, the cylinders in each set being offset longitudinally with respect to the crank shaft and the cylinders of one set being staggered with respect to the cylinders-in the other set; power pistons in said cylinders; connecting rods for one set of pistons connected alongside of each other to one of the cranks; connecting rods for the other set of pistons similarly connected to the other crank; an enlarged fuel pumping piston at the inner end of each power piston; a fuel pumping cylin der extending inwardly from each radial cylinder;

and conduits connecting the fuel cylinders of each set to the staggered p'ower cylinders of the other set.

6. A two-cycle internal combustion engine comprising, in combination, a crank case; a crank shaft in the crank case having a min of cranks arranged 180 degrees apart; two circumferential and overlapping sets of radial power cylinders for each crank connected to the crank case, the cylinders in each set being offset longitudinally with respect to the crank shaft and the cylinders of one set being staggered with respect to the cylinders in the other set; power pistons in said cylinders; connecting rods for one set of pistons connected alongside of each other to one of the cranks; connecting rods for the other set of pistons similar connected to the other crank; an enlarged fuel pumping piston at the inner end of each power piston; a relatively large sheet metal fuel pumping cylinder projecting into the crank case from the inner end of each power cylinder;

and fuel conduits connecting the fuel cylinders of each row to the adJacent power cylinders of the other row.

7. A two-cycle internal combustion engine comprising, in combination, a substantially cylindrical crank case; two overlapping circumferential rows of radial cylinders connected to the crank case with the cylinders in one row staggered with respect to the cylinders in the other row, there being an odd number of cylinders in each row; a crank shaft having a pair of crank pins each connected to all of the pistons in one row /of said cylinders; and fuel mture pumps associated with the respective pistons arranged to supply fuel charges to the next adjacent staggered cylinders, the positions of the cranks and the timing being such that explosions occur simultaneously in two cylinders on opposite sides of the crank shaft one in one row and the other in the other row.

8. A two-cycle internal combustion engine comprising, in combination, a crank case; circumferential overlapping rows of stepped radial cylinders connected to the crank case, each having an enlarged cylindrical sleeve, projecting into the crank case, the cylinders in one row being staggered with respect to the cylinders in the other row and an oddnumber of cylinders being arranged in each row; stepped pistons in the cylinders providing fuel pumps in the enlarged cylindrical sleeves; a crank shaft having cranks arranged 180 degrees apart each connected to all of the pistons in one row; said cylindrical sleeves having intake ports at their inner ends adapted to be uncovered by the fuel pumping pistons at the inner ends of their strokes; fuel charging conduits connecting the outer ends of fuel pumping cylinders to the next adjacent power cylinders; and a carburetor connected to supply fuel mixture to the crank case, the timing being such that when one piston is nearing the end of its compression stroke, fuel is pumped into the next adjacent cylinder of the other row opposite to the direction of rotation of the crank shaft.

9. In a two-cycle internal combustion engine, two staggered and overlapping rows of radial power cylinders, comprising, an odd number of cylinders in each row; coaxial fuel pumping cylinders at the inner ends of said power cylinders; stepped pistons in said cylinders; a crank shaft having a pair of crank pins arranged 180 degrees apart and connected to all of the pistons in the respective rows of cylinders; and means whereby fuel charges are delivered from the crank case by the fuel pistons in one row to the adjacent power cylinders in the other row. a

10. In a ,two-cycle internal combustion engine, two staggered and overlapping rows of radial power cylinders, three cylindersbeing arranged in each row; coaxial fuel pumping cylinders at the inner ends of said power cylinders; stepped, one-piece pistons in said cylinders; a

crank shaft having a pair of crank pins arranged 180 degrees apart and connected to all of the pistons in the respective rows of cylinders; and means whereby fuel mixture is delivered by each fuel pump into the adjacent power cylinder of the other row in the direction opposite to the direction of rotation of the crank shaft.

11. In a'two-cycleinternal combustion engine having two overlapping rows of staggered cylinders, fuel charging pumps associated with the pistons in each cylinder and connected to supply fuel to the respective adjacent cylinders in the other row.

12. In a two-cycle engine of the class described, a substantially cylindrical crank case; two circumferential rows of radial cylinders connected to the crank case; cylindrical sleeves associated with said cylinders and projecting into a the .cranlr case to provide fuel charging cylinders; stepped pistons in said cylinders; intake ports in said sleeves on the inside of the crank case; and intake conduits within the crank case leading from one end thereof to said intake ports whereby to prevent lubricating oil from being thrown integrally into 'the fuel mixture.

7 13. In a two-cycle engine of the class described, a substantially cylindrical crank case; two-"circumferential rows of radial cylinders connected to the crank case; cylindrical sleeves associated with said cylinders and projecting into the crank case-to provide fuel charging cylinders; stepped pistons in said cylinders; intake ports in said sleeves on the inside of the crank case; said crank case having inwardly extending ribs; and sheet metal plates secured to said ribs adjacent to the ported ends of said cylindrical sleeves to provide fuel intake conduits leading from one end of the crank case whereby to prevent lubricating oil from being thrown centrifugally into the fuel mixture entering said ports.

JULIUS SCHU'BERT. 

